Polarized image-projection system



ENCE SEARCH 300% SR MgEFER 3 W V May 16, T967 M. V. SHELANSKI POLARIZEDIMAGE-PROJECTION SYSTEM Original Filed Aug. 25, 1962 INVENTOR.

MORRIS V. SHELANSKI ATTORNEY United States Patent 3,319,519 POLARHZEDIMAGE-PROJEtTTION SYSTEM Morris V. Shelanslai, 431 Wister Road,Wynnewood, Pa. 19096 Original application Aug. 23, 1962, Ser. No.219,026, new

Patent No. 3,235,631, dated Feb. 15, 1966. Divided and this applicationAug. 25, W65, Ser. No. 482,537

1 Claim. (CL 33-24) This invention is a division of application SerialNo. 219,026, filed August 23, 1962, now Patent No. 3,235,631 and relatesto light polarizing materials, and it particularly relates to novelpolarizing materials and to novel processes for the production andutilization thereof.

It was heretofore known to produce a light-polarizing polymeric film bystretching the film in a certain direction whereby the molecules in thestretched film became oriented in that direction so that when the filmwas thereafter stained with iodine, light in only one plane waspermitted to pass through. In these prior methods, it was necessary tostretch and stain strips of film and then cut the film into sections.The sections then had to be mounted at different angles on a singleplane so that light polarized at different angles would pass through acorrespondingly polarized section while being prevented from passingthrough the others.

A very serious disadvantage of the above type of method was the factthat painstaking care and skill were required to stretch, stain, out andmount the polarized sections in the proper positions and orientations,and it was very diflicult, if not impossible, to duplicate a variablypolarized film assembly made in this manner because of the manyindividual hand operations involved. The result was that the film wasexceedingly expensive and difficult to obtain. Furthermore, there couldnever exist the certainty that one such film asembly would besufficiently like another to permit them to be used interchangeably.

It is one object of the present invention to overcome the disadvantagesmentioned above by providing a simple, easy, rapid and inexpensiveprocess for obtaining variably polarized film.

Another object of the present invention is to provide an improvedprocess of the aforesaid type wherein the identical product may bereproduced as often as desired whereby complete standardization isattained, interchangeability achieved, and mass production madepossible.

Another object of the present invention is to utilize the variablypolarized films produced in the present manner to obtain highlyeffective illusions of animation and motion without the use of motionpicture apparatus or technique.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following description when read in conjunction with theaccompanying drawings wherein:

FIG. 1 is a fragmentary perspective view of one type of apparatus usedto produce the polarized film of this invention.

FIG 2 is a fragmentary perspective view of a second type of apparatusutilizable in the practice of this invention.

FIG. 3 is a fragmentary perspective View of a third type of apparatusutilizable in the practice of this invention.

FIG. 4 is a fragmentary, somewhat diagrammatic, perspective view of afourth type of apparatus utilizable in the practice of this invention.

FIG. 5 is a diagrammatic view showing one utilization of the presentinvention.

FIG. 6 is a diagrammatic view showing a second type of utilization ofthe present invention.

FIG. 7 is a diagrammatic view showing a third type of utilization of thepresent invention.

In acordance with the present invention, it has now been discovered thatorientation of the molecules in a film and consequent polarization canbe achieved not only by stretching in the plane of the film but also byapplying pressure in a plane transverse to the surface plane of thefilm. This pressure may be a surface pressure such as caused bypolishing or buffiing, or it may be a penetrative pressure wherebyindentations or grooves are scribed into the surface. However, when ascribing or penetrative pressure is used, care must be taken to avoidpiercing the film through from the front to the rear surface since suchcomplete penetration would only serve to remove all the film in thatspot or area.

The polarization by means of scribing or bufiiing makes it possible touse dies or rollers of uniform preformed configuration whereby eachpiece of treated polarized film is always identical with each otherpiece so treated since identical patterns and pressures are always used.One manner of accomplishing this is shown in FIG. 1 where a die roller10 is mounted on a shaft 12 connected to a drive means (not shown). Theperiphery of the roller 10 is provided with a plurality of embossedpatterns 14 of predetermined configuration. These inscribed patterns areidentical to each other and each contains a plurality of square orrectangular sections, each section containing inscribed lines or ribsextending in a direction and angle different from the lines or ribs inthe other sections. The size, number, form, etc., of the sections may bevaried as desired. A strip of film 16 is passed underneath the roller 10in such a. manner that the roller exerts a predetermined amount ofpressure on the strip while it simultaneously rotates on its axis. Thiscauses indented patterns 18 to be inscribed on the strip as it passesunder the rotating roller.

Instead of a roller-type die, a stamping plate or punch may be used.This is illustrated in FIG. 2 where there is shown a verticallyreciprocable die plate 20 mounted on a rod 22 attached to areciprocating means (not shown) The underface of the die plate isprovided with an embossed or ribbed pattern 24 similar to those providedon the roller die of FIG. 1. The reciprocable die or plunger 20 isillustrated as scribing a pattern 28 on a strip of prepared film 26which moves linearly thereunder in timed relationship to thereciprocation. The timed relationship can be effected by any one of agreat many standard mechanisms and further illustration or descriptionof a particular mechanism is not here necessary. The die plate 20 mayalso, if desired, by used manually for inscribing individual plates.

The effective pressure of the scribing apparatus (either in the form ofthe roller or punch) may be straight down or it may be somewhat angularwhereby there is a compound pressure both in the vertical and horizontaldirection. This angular pressure is obtained by making the scribinglines or ribs of the pattern angular. The angular scribing is preferablesince it provides a wider divergence of molecular orientation.

As indicated above, polarization may also be obtained by surfacepressure such as caused by bufiing or polishing. This surface pressureeffect can be used to form definite patterns by using a buffing orpolishing wheel which is given compound movement, to wit, rotation onits axis for the surface pressure and a twisting or angular movement onan axis transverse to its axis of rotation. This type of apparatus isillustrated in FIG. 3 where a buifing wheel or roller 30 is mounted forrotation on a shaft 32 journaled in bearings 34 integral with a yoke 36.

A motor 38 is operatively connected to the shaft 32 and to a source ofelectrical energy (not shown), the motor being used to rotate the shaft32 in its bearings 34. The yoke 36 is integral with an upwardlyextending rod 40 which is, in turn, operatively connected to a secondmotor (not shown) for rotation thereby. By means of this construction,while the roller 30 rotates on its axis 32, the entire yoke assembly issimultaneously rotated in conjunction with the rotation of rod 40.Consequently, as the strip of film 42 moves linearly, the buffing roller30 exerts both a downward and a twisting pressure on its surface wherebya pattern, indicated at 44, is formed. This pattern conforms to theconstantly changing pressure areas, as diagrammatically shown.

Although the apparatus of FIG. 3 has been described in conjunction withtwo separate motors, one motor may be used for providing both rotations,such motor being operatively connected, in well-known manner, to boththe shaft 32 and rod 40 by means of gears or belts or other suchmechanical expedients.

Before the film strip, coated plate, or the like, has been molecularlyoriented by one of the above methods, it is stained with aniodine-containing stain by dipping, spraying, painting or any otherdesirable method. Dipping is preferred because it provides the fullestarea coverage and deepest penetration of the stain into the film wherebythe film is, in effect, impregnated. In this manner, a relatively deepimpression may be inscribed in the film, when scribing apparatus isbeing used, without cutting through the stained layer.

The iodine solution should be applied in sufiicient quantity to effect adeep blue color in the film after the stained film has been allowed tostand for some minutes. It has been found that if the film is slightlymoistened with water prior to application of the iodine solution or ifthe iodine solution is applied while the film is in a moist or dampatmosphere, the desirable deep blue color is most easily and effectivelyobtained.

In addition to the methods utilizing either scribing or buffing of apreviously iodine-stained film, as described above, the polarization maybe carried out by imprinting the film directly with an iodine-containingstaining solution whereby a pattern is formed similar to those formedwith the apparatus of FIGS. 1, 2 and 3. Such an im printing method isillustrated in FIG. 4 where a printing roller 48, having embossedpatterns 50 on its periphery, is mounted on a drive shaft 52 connectedto a standard drive means (not shown). The roller 48 is fed with astaining solution from a trough 54 during one portion of its rotationand imprints the patterns on the linearly moving film strip 56 duringanother portion of its rotation. The staining solution is applied to theprinting roller 48 by means of one or more applicator rollers such asindicated at 58. In the same manner, a reciprocating, plunger-typeprinting die head may be used similar to the inscribing apparatus shownin FIG. 2.

The film or coating used in the present invention is a polymericmaterial and preferably polyvinyl alcohol. In this respect, good resultshave been obtained with an incompletely hydrolized polyvinyl acetatewherein about 90 percent of the groupings are polyvinyl alcohol andabout percent are acetate groupings.

The staining solution is preferably a mixture of iodine and an alkalimetal iodide such as potassium iodide in approximately equal molecularproportions.

Illustrative of the manufacture of films utilized in the presentinvention are the following examples, no intent being here implied tolimit the invention otherwise than as claimed:

Example 1 10 g. of polyvinyl alcohol (Elvanol 7105 produced by E. I. duPont de Nemours & Co., Inc., Wilmington, Del.) were dissolved in 100 ml.of water at a temperature of about 10-100 C. This solution was depositedon the surface of a strip of cellulose triacetate in amount of about 16mg. of solution per square inch of strip. The coated strip was thendried in air for 24 hours at room temperature, resulting in theformation of a solid film of polyvinyl alcohol on the surface of thestrip. The film was then stained with a staining solution.

The staining solution comprised about 250 mg. iodine and about 175 mg.potassium iodide, the solution being diluted to about 25 ml. with methylalcohol. This staining solution was poured over the film and allowed todry, resulting in a deposition of about 1 ml. of the staining solutionfor each square inch of film. The staining solution dried almostimmediately and the film was ready for polarization.

Example 2 The same procedure was followed as in Example 1 above exceptthat in place of Elvanol 7105, there was substituted a similar amount ofElvanol 52-22 made by the same manufacturer but containing about 10-11percent acetate groupings, the remainder being polyvinyl alcohol. Theresulting film proved to be substantially similar to that produced inExample 1 insofar as its ability to be polarized was concerned, bothbeing excellently polarized by surface pressure techniques such asillustrated in the drawings and described above.

It is to be understood that although the film has been specificallydescribed as a coating on a base, 'it may be formed in any other desiredmanner within the scope of the present invention. For example, it may bemade by casting, extruding, etc. in the form of a unitary shaped bodyrequiring no support base.

Furthermore, the Oriented and stained filrn may have imposed thereon adesired design or picture and then be encapsulated between two flattransparent sheets or plates whereby a permanent, protected assembly isprovided. This is especially desirable when the film is to be used onbillboards, or the like, which are constantly exposed to rain, snow andthe other elements.

FIG. 5 illustrates one use of the present invention wherein directviewing is provided. In this illustration, a film 60, stained,molecularly oriented and imprinted with a desired image or design, ismounted in front of a rotatable, polarized, transparent disc 62, thedisc 62 being positioned between the film 60 and a source of light 64.Upon viewing the image on the film 60 from the position illustrated bythe eye 66 and when the disc 62 is rotating, the differently polarizedareas of the film will permit light from the source 64 to passtherethrough in accordance with the corresponding rotatable position ofthe disc, the polarized plane of the disc being continuously changed inits position as the disc rotates. In each rotative position of the discits plane of polarization, therefore, corre sponds with the polarizedplane of a different polarized area of the film and consequently asdifferent areas of the film light up, there is an illusion of movementof the image thereon.

In FIG. 6, the present invention is illustrated for the purpose ofprojecting an image on a screen in the manner of a slide but with theillusion of motion. The apparatus illustrated comprises a source oflight 70 and a lens 72 between which is positioned a treated film 74which has been stained, molecularly oriented and upon which an image hasbeen imposed. A viewing screen 76 is aligned with the lens 72 andbetween the lens and the screen is rotatably positioned a polarized disc78 similar to disc 62. As the disc 78 rotates, it permits light from thesource to pass through the different polarized areas of the film 74 andas the images on these different areas are projected onto the screen,there is an illusion of motion when viewed from a position such asindicated at 80.

In FIG. 7 there is illustrated an arrangement wherein the invention isapplied to a billboard or the like. In this arrangement the billboard isillustrated as having a reflective surface 92 with the treated film 94,similar to films 6t and 74, in spaced relation thereto. However, inpractice, the film may, and perferably is, mounted directly on thereflector surface 92. Between the fihn 94 and a source of light 96 ismounted a rotatable polarized disc 98, similar to discs 62 and 72. Asthe disc 98 rotates, an illusion of motion is created on the exposedfront surface of the film 94 when viewed from a position such asindicated at 100.

In the arrangement illustrated in FIG. 5, the polarized disc is shownbetween the source of light and the treated film, while in thearrangement of FIG. 6, the treated film is shown between the source oflight and the polarized disc. The invention has been so illustrated toshow that it is a matter of choice as to the relative positions of thefilm and polarized disc in relation to the source of light since thedesired effect will be obtained in either arrangernent.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is, therefore, to beunderstood that within the scope of the appended claim, the inventionmay be practiced otherwise than as specifically described.

The invention claimed is:

An image-projection system comprising a composite including a filmconsisting at least partially of polyvinyl alcohol and having a frontsurface covered with an iodine-containing stain, said front surfacebeing divided into a plurality of polarized areas, at least two of saidareas having different planes of polarity, said front surface beingfully exposed to view, said film having a rear surface that is inface-to-face parallel arrangement with a reflective surface, a source oflight in spaced relation to said front surface, said front surface beingexposed to the light rays from said source, a rotatable polarizing discmeans for selectively varying the polarity of the light from saidsource, said disc means being positioned between said source and saidfront surface, and said reflective surface being constructed andarranged to direct the light toward an observer positioned in front ofsaid front surface.

References Cited by the Examiner UNITED STATES PATENTS 2,165,974 7/1939Land 8865 2,237,567 4/1941 Land 2642 2,882,631 4/1959 Boone 88-652,977,845 4/1961 Boone 8865 3,104,273 9/1963 Ballance 8865 3,177,7654/1965 Yates 8865 3,254,561 6/1966 Makas 88-65 NORTON ANSHER, PrimaryExaminer.

R. M. SHEER, Examiner.

